A gas cap left off, loose or not sealing (most common, often right after refueling). A disconnected or split EVAP hose. A purge valve stuck closed or a vent valve stuck open. A cracked charcoal canister or filler neck.

Trouble codes › P0455

P0455 Evaporative Emission System Leak Detected (Large Leak)

Q: What does P0455 mean?

P0455 means the EVAP system has a large leak, most often a loose, missing or bad gas cap. The engine computer tried to pull a vacuum on the EVAP system (the system that stores fuel vapor from the tank) and couldn't, which means a large leak or an opening such as a missing gas cap.

EVAP

P0455 means the EVAP system has a large leak, most often a loose, missing or bad gas cap.

The engine computer tried to pull a vacuum on the EVAP system (the system that stores fuel vapor from the tank) and couldn't, which means a large leak or an opening such as a missing gas cap.

Can I keep driving? Yes, for now.

Safe to drive, but you may smell fuel and it will fail an emissions test. If the smell is strong inside the car, find the leak soon.

Common causes

A gas cap left off, loose or not sealing (most common, often right after refueling)
A disconnected or split EVAP hose
A purge valve stuck closed or a vent valve stuck open
A cracked charcoal canister or filler neck

Symptoms

Check-engine light, often a day or two after filling up
Fuel smell, sometimes
On some vehicles, trouble filling the tank (the pump nozzle keeps clicking off) if the vent side is involved

Common on: Ford F-150, Toyota Camry, Toyota RAV4, Ford Escape, Ford Explorer, Ford Fusion

What to check first

Check that the gas cap is on and tightened until it clicks; inspect its seal.
Clear the code and drive for a few days to see whether it returns.
Look over the EVAP hoses from the engine back to the canister near the tank for anything disconnected or cracked.
If it returns, a smoke test of the EVAP system will show the leak; the purge and vent valves can be tested with a scan tool on many vehicles.

What does P0455 mean on your vehicle?

The likely cause depends on your engine. iRepair researches your exact year, make, model and engine (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.

Ask iRepair about P0455

No scanner? Most auto parts stores read check-engine codes for free.

Related codes

General guidance for P0455 on most vehicles. Some makers use the same code a little differently; confirm in the service information for your vehicle, put safety first, and see a professional when in doubt.